Apple approved Google voice app to be listed in their app store, albeit it's not the official or original version of Google, but with it your iPhone 4 can have full access to Google voice account. The app name is Google Voice (GV) Connect.
Last year Apple decided to delist the official Google Voice app, which not just made the Mountain-View based company unsatisfied also bringing discontent among several iPhone users. Based on Apple explanation, the reason they did that because of duplicating issues and now the app, though it's not the official one, is back and waiting for you to grab for $2.99 in iTunes.

What do you think, is this app worth $2.99 from your wallet? Or it's better to wait for the Apple's approval for the official Google version which is nobody knows when?